1. Field of the Invention
The present invention relates to a blood rheology measurement device and a blood rheology measurement method which measure blood rheology indicating a fluidity generally referred to as fluidity/viscosity of blood, more particularly to a technology to measure a flow of blood flowing through an artery, ascertain a micro circulating blood flow as a base of activity of human body tissue, and perform evaluation of health, diagnosis of disease, evaluation of effect of medicine and the like.
2. Description of the Related Art
To perform evaluation of human health, diagnosis of disease, evaluation of medicine effect on human body, evaluation of soundness and functionality of food and the like, heretofore blood rheology has been measured to perform the evaluation or the diagnosis from measurement results. As a conventional technology using a blood fluidity measurement device, there is known a method in which blood is sampled from a subject, and the blood rheology is measured from a time for which the blood passes under a constant pressure by use of a micro channel array prepared by a lithographic process (see “Measurement of Fluidity of Whole Blood by use of Capillary Blood Vessel. Model” (Food Research Result Information, No. 11 issued in 1999)).
However, in the blood rheology measurement method using the micro channel array as in the conventional technology, to sample the blood from the subject, an injection needle has to be stuck to an elbow part to sample the blood. Therefore, if an in vitro test is performed to check an influence of a food ingredient on the blood rheology, there is a problem that the blood cannot be sampled from the same person many times a day, and it is difficult to continuously perform the test. If the person tries to sample his own blood to measure the blood rheology at home or the like outside a medical institution by the blood fluidity measurement device as in the conventional example, this is impossible because the device cannot be installed, and an appropriate treatment cannot be performed at home. Therefore, there is a problem that the rheology can be measured in the medical institution only.
On the other hand, it is considered that there is a strong correlation between the blood rheology and a blood flow rate in an artery of a living body. That is, it is supposed that the blood flow rate is low in a case where blood viscosity is high, and high in a case where the viscosity is low. Therefore, the blood flow rate in the living body can be measured to know the blood rheology indirectly (see, e.g., Japanese Patent Application Laid-Open No. 2003-159250).
However, in a case where the measurement is non-invasively performed, it is difficult to grasp a position of the artery in the living body in detail. Therefore, a positional relation between a sensor and the artery might differ every time the relation is measured. There is disadvantageously a possibility that a change of the blood rheology with elapse of time cannot be correctly evaluated during measurement of the change with the elapse of time.
An object of the present invention is to provide a blood rheology measurement device which measures a positional relation between an artery in a living body and a sensor on the same conditions for each subject during non-invasive measurement and which correctly evaluates a change of blood rheology with elapse of time.